fix: skill upload 200-file cap + packaging hygiene (3.0.1)

[mvanhorn]

Summary

claude.ai's "Upload skill" UI rejects zips with more than 200 files. Zipping this repo produced 406 files, so direct upload failed. This PR fixes that plus related packaging hygiene.

• Removes unused root vendor/ (215 files from accidental PR feat: add Xiaohongshu source + Reddit public fallback (and probe reliability fix) #48 commit; real vendored X client stays at scripts/lib/vendor/bird-search/)
• Removes legacy top-level plans/ (superseded by docs/plans/)
• Adds .gitattributes with export-ignore entries that mirror Anthropic's canonical skill-packager exclusions plus repo-specific dev/docs/media/internal-skill excludes
• Adds scripts/build-skill.sh - one-command builder that produces dist/last30days.skill with a single top-level last30days/ directory, enforces =200 files and exactly one SKILL.md, and refuses dirty-tree builds
• Trims SKILL.md description from 228 to 167 chars (Anthropic caps at 200)
• Bumps version to 3.0.1 across SKILL.md, skills/last30days/SKILL.md, plugin.json, gemini-extension.json

Verification

• bash scripts/build-skill.sh - 90 files, 264K, exactly one SKILL.md, no symlinks in archive
• python3 -m pytest tests/test_bird_x.py - 9 passed (proves bird-search runtime intact)
• python3 -m pytest tests/test_version_consistency.py - 2 passed (version alignment)
• Runtime import audit: all non-stdlib imports resolve to lib.*, store, or scripts.* - zero reach into excluded paths
• Pre-existing test_store.py / test_watchlist_commands.py failures confirmed present on main before these changes (not introduced here)

Plan

Full plan at docs/plans/2026-04-14-001-fix-skill-upload-200-file-limit-plan.md.

Out of scope (separate PRs)

• Plugin fails to load in Claude Code: "Path escapes plugin directory: ./ (skills)" #239 "skills": ["./"] plugin-loader path-escape
• OpenClaw package 3.0.0-open ships broken path references in published SKILL.md #236 OpenClaw broken path references
• Security findings from ClawGuard scan for mvanhorn/last30days-skill #231 ClawGuard security findings
• Version and SKILL.md inconsistencies after v3 rename #190 other version drift (gemini-extension was already at 3.0.0, not 2.9.5 as Version and SKILL.md inconsistencies after v3 rename #190 claims)
• Cannot install skill for Gemini CLI #184 Gemini CLI install

Test plan

• Build-skill script produces valid .skill file
• Archive contains exactly one SKILL.md at last30days/SKILL.md
• No symlinks or nested skills/ directories in archive
• bird_x tests pass after vendor/ delete
• Version consistency tests pass after bump
• Manual: upload dist/last30days.skill to claude.ai via the "Upload skill" UI and confirm acceptance (the final rejection-risk gate)

Post-Deploy Monitoring & Validation

No runtime behavior changes ship in this PR - it is pure packaging hygiene and metadata updates. Skill consumers (Claude Code plugin via GitHub URL, ClawHub publish path, Gemini extension) see the same runtime.

Validation:

• Watch the next 48 hours of GitHub issues for anyone reporting install/load failures on 3.0.1 vs 3.0.0
• If the manual claude.ai upload test passes, the primary goal is met
• Rollback trigger: any report that the plugin install via Claude Code or gemini extensions install starts failing on 3.0.1. Mitigation: revert the version bump and republish 3.0.0 with the packaging fixes.

Owner: @mvanhorn. Window: 48 hours post-merge.

Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com