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/remove_github_members.sh

@@ -0,0 +1,52 @@
+#!/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!"