feat: reorganise bash scripts and add comprehensive documentation (#6)

## Summary

This PR completes the bash script restructuring and adds comprehensive documentation across all script categories.

### Bash Restructuring

- Moved cohort shell scripts (`remove_github_members.sh`, `update_github_teams.sh`) from `python/cohort/` into a new `bash/cohort/` directory
- Moved existing bash utilities (`add-keys-to-git.sh`, `fix-yubikey-perms.sh`, `list-yubikey-ssh-keys.sh`) into a new `bash/yubikey/` subdirectory
- Updated `run.sh` to support **Bash** as a third language option alongside TypeScript and Python
  - Bash scripts are run directly (no 1Password secret injection needed)
  - Category discovery and script listing works the same as for TS/Python
  - Removed dead "Root Scripts" logic that was no longer needed

### Documentation

Added `README.md` files for all script categories that were missing them:

- `bash/cohort/README.md` — cohort GitHub team management scripts
- `bash/yubikey/README.md` — YubiKey SSH key and permission utilities
- `typescript/src/crowdin/README.md` — Crowdin translation management scripts
- `typescript/src/discord/README.md` — Discord bot utility scripts
- `typescript/src/discourse/README.md` — Discourse forum management scripts
- `typescript/src/gitea/README.md` — Gitea bulk repository operation scripts
- `typescript/src/github/README.md` — GitHub API interaction scripts
- `typescript/src/music/README.md` — Music file metadata tools
- `typescript/src/s3/README.md` — S3-compatible object storage scripts
- `typescript/src/security/README.md` — Security analysis and reporting scripts
- `python/cohort/README.md` — Updated to remove moved shell scripts, fix usage commands

Also updated project-level docs:

- **`README.md`** — Corrected project structure, fixed running instructions (removed references to non-existent `make run-ts`/`make run-py` targets), added Bash prerequisites
- **`CLAUDE.md`** — Updated project overview, structure, development standards, and script-adding guides to reflect the current state of the project

✨ This PR was created with help from Hikari~ 🌸

Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Reviewed-on: #6
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

bash/cohort/README.md

@@ -0,0 +1,75 @@
+# Cohort Bash Scripts
+
+Shell scripts for managing GitHub team membership during the NHCarrigan spring cohort programme. These scripts handle one-off team changes that are too complex or bulk-oriented to do manually through the GitHub web interface.
+
+All scripts use the `gh` CLI for GitHub API calls. Run `gh auth login` before using them.
+
+## Getting Started
+
+Run scripts via the interactive runner from the project root:
+
+```bash
+make run
+# Select: Bash → cohort → <script>
+```
+
+Or run directly:
+
+```bash
+bash bash/cohort/<script-name>.sh
+```
+
+## Table of Contents
+
+- [remove\_github\_members.sh](#remove_github_memberssh)
+- [update\_github\_teams.sh](#update_github_teamssh)
+
+---
+
+## remove_github_members.sh
+
+Removes a hardcoded list of inactive members from their GitHub organisation teams in the `nhcarrigan-spring-2026-cohort` organisation. Covers both standard team membership and `-leaders` sub-team membership where applicable.
+
+### Usage
+
+```bash
+bash bash/cohort/remove_github_members.sh
+```
+
+### Environment Variables
+
+None. Uses `gh` CLI authentication — run `gh auth login` first.
+
+### Data Files
+
+None. Member usernames and team slugs are hardcoded in the script.
+
+### Notes
+
+- The member list and team assignments are specific to a point-in-time removal event. Update the script with the correct usernames before each use.
+- Each removal command uses `|| true` so a single failure (e.g. member already removed) does not abort the entire script.
+
+---
+
+## update_github_teams.sh
+
+Orchestrates a multi-step GitHub team restructure: removes all members from a dissolved team, clears its leaders sub-team, then adds each member to their new team. Also promotes a member to leader in their new team.
+
+### Usage
+
+```bash
+bash bash/cohort/update_github_teams.sh
+```
+
+### Environment Variables
+
+None. Uses `gh` CLI authentication — run `gh auth login` first.
+
+### Data Files
+
+None. All member usernames, team slugs, and role assignments are hardcoded in the script.
+
+### Notes
+
+- This script is specific to a one-off team restructure (Jade Jasmine dissolution). Update the member list and team assignments before each use.
+- The script exits immediately on any error (`set -e`). If a step fails, check whether the member or team already exists in the target state.

bash/cohort/remove_github_members.sh

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+#!/usr/bin/env bash
+# Script to remove inactive members from GitHub organization teams
+# Date: 2026-02-12
+
+ORG="nhcarrigan-spring-2026-cohort"
+
+# Team 1 (Jade Jasmine) - Remove leader and participant
+echo "Removing from Jade Jasmine..."
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine-leaders/memberships/Mista-Log" || true
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/A-normal-programmer" || true
+
+# Team 2 (Crimson Dahlia) - Remove 2 participants
+echo "Removing from Crimson Dahlia..."
+gh api --method DELETE "/orgs/$ORG/teams/crimson-dahlia/memberships/1s-crypto" || true
+gh api --method DELETE "/orgs/$ORG/teams/crimson-dahlia/memberships/emlanis" || true
+
+# Team 3 (Rose Camellia) - Remove leader
+echo "Removing from Rose Camellia..."
+gh api --method DELETE "/orgs/$ORG/teams/rose-camellia-leaders/memberships/michaelboateng1" || true
+
+# Team 4 (Amber Wisteria) - Remove leader and participant
+echo "Removing from Amber Wisteria..."
+gh api --method DELETE "/orgs/$ORG/teams/amber-wisteria-leaders/memberships/neonbit101" || true
+gh api --method DELETE "/orgs/$ORG/teams/amber-wisteria/memberships/avanishchandra" || true
+
+# Team 5 (Ivory Orchid) - Remove participant
+echo "Removing from Ivory Orchid..."
+gh api --method DELETE "/orgs/$ORG/teams/ivory-orchid/memberships/VuBui217" || true
+
+# Team 7 (Peach Gardenia) - Remove participant
+echo "Removing from Peach Gardenia..."
+gh api --method DELETE "/orgs/$ORG/teams/peach-gardenia/memberships/TabsOO7" || true
+
+# Team 8 (Violet Carnation) - Remove 2 participants
+echo "Removing from Violet Carnation..."
+gh api --method DELETE "/orgs/$ORG/teams/violet-carnation/memberships/masudulalam" || true
+gh api --method DELETE "/orgs/$ORG/teams/violet-carnation/memberships/urmilbhatt" || true
+
+# Team 10 (Coral Sunflower) - Remove leader and participant
+echo "Removing from Coral Sunflower..."
+gh api --method DELETE "/orgs/$ORG/teams/coral-sunflower-leaders/memberships/AjayTheWizard" || true
+gh api --method DELETE "/orgs/$ORG/teams/coral-sunflower/memberships/Hritikhh" || true
+
+# Team 11 (Indigo Tulip) - Remove participant
+echo "Removing from Indigo Tulip..."
+gh api --method DELETE "/orgs/$ORG/teams/indigo-tulip/memberships/SiAust" || true
+
+# Team 13 (Mint Narcissus) - Remove participant
+echo "Removing from Mint Narcissus..."
+gh api --method DELETE "/orgs/$ORG/teams/mint-narcissus/memberships/SergioPardoSanchez" || true
+
+echo "Done removing members from GitHub teams!"

bash/cohort/update_github_teams.sh

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+#!/bin/bash
+# Update GitHub teams for Jade Jasmine dissolution
+
+set -e  # Exit on error
+
+ORG="nhcarrigan-spring-2026-cohort"
+
+echo "=== Phase 2: GitHub Team Changes ==="
+echo ""
+
+# Step 1: Remove all members from jade-jasmine team
+echo "Step 1: Removing members from jade-jasmine team..."
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/Nikil-D-Gr8" || echo "  - Nikil-D-Gr8 already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/amandaw800" || echo "  - amandaw800 already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/hayden-html" || echo "  - hayden-html already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/hbar1st" || echo "  - hbar1st already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/rosacabrerac" || echo "  - rosacabrerac already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/ArbitraryPie" || echo "  - ArbitraryPie already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/builtbykabir" || echo "  - builtbykabir already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine/memberships/Mista-Log" || echo "  - Mista-Log already removed or not found"
+echo "✅ jade-jasmine team cleared"
+echo ""
+
+# Step 2: Remove leaders from jade-jasmine-leaders team
+echo "Step 2: Removing leaders from jade-jasmine-leaders team..."
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine-leaders/memberships/hayden-html" || echo "  - hayden-html already removed or not found"
+gh api --method DELETE "/orgs/$ORG/teams/jade-jasmine-leaders/memberships/Mista-Log" || echo "  - Mista-Log already removed or not found"
+echo "✅ jade-jasmine-leaders team cleared"
+echo ""
+
+# Step 3: Add members to new teams
+echo "Step 3: Adding members to new teams..."
+
+echo "  - Adding Nikil-D-Gr8 to crimson-dahlia..."
+gh api --method PUT "/orgs/$ORG/teams/crimson-dahlia/memberships/Nikil-D-Gr8" -f role=member
+
+echo "  - Adding amandaw800 to violet-carnation..."
+gh api --method PUT "/orgs/$ORG/teams/violet-carnation/memberships/amandaw800" -f role=member
+
+echo "  - Adding hayden-html to teal-iris..."
+gh api --method PUT "/orgs/$ORG/teams/teal-iris/memberships/hayden-html" -f role=member
+
+echo "  - Adding hbar1st to indigo-tulip..."
+gh api --method PUT "/orgs/$ORG/teams/indigo-tulip/memberships/hbar1st" -f role=member
+
+echo "  - Adding rosacabrerac to scarlet-hydrangea..."
+gh api --method PUT "/orgs/$ORG/teams/scarlet-hydrangea/memberships/rosacabrerac" -f role=member
+
+echo "  - Adding ArbitraryPie to peach-gardenia..."
+gh api --method PUT "/orgs/$ORG/teams/peach-gardenia/memberships/ArbitraryPie" -f role=member
+
+echo "  - Adding builtbykabir to azure-lotus..."
+gh api --method PUT "/orgs/$ORG/teams/azure-lotus/memberships/builtbykabir" -f role=member
+
+echo "  - Adding Mista-Log to ivory-orchid..."
+gh api --method PUT "/orgs/$ORG/teams/ivory-orchid/memberships/Mista-Log" -f role=member
+
+echo "✅ All members added to new teams"
+echo ""
+
+# Step 4: Add Mista-Log to ivory-orchid-leaders
+echo "Step 4: Adding Mista-Log to ivory-orchid-leaders..."
+gh api --method PUT "/orgs/$ORG/teams/ivory-orchid-leaders/memberships/Mista-Log" -f role=member
+echo "✅ Mista-Log promoted to leader in Ivory Orchid"
+echo ""
+
+echo "=== Phase 2 Complete! ==="
+echo ""
+echo "Summary:"
+echo "- ✅ jade-jasmine team cleared (8 members removed)"
+echo "- ✅ jade-jasmine-leaders team cleared (2 leaders removed)"
+echo "- ✅ 8 members added to their new teams"
+echo "- ✅ Mista-Log promoted to leader in ivory-orchid"