feat: add Amp (ampcode.com) as a supported platform (scoped resubmission of #790)

[zuwasi]

Scoped resubmission of #790, addressing both bugs flagged in the review and dropping all unrelated changes.

What's in this PR

Four files only, exactly as requested:

1. graphify/skill-amp.md (new) — Amp-specific skill, adapted from skill-codex.md. Differences from the Codex variant:

   • Uses Amp's Task tool for parallel subagent dispatch (multiple Task calls in the same response run concurrently)
   • References AGENTS.md instead of CLAUDE.md for the always-on integration
   • Drops Codex-specific spawn_agent / multi_agent config notes
   • Acknowledges that Amp's Task tool does not expose per-call token usage, so cost is reported as "not available"

2. graphify/__main__.py — adds _PLATFORM_CONFIG["amp"] and "amp" to the agents-install dispatch tuple:

   "amp": {
       "skill_file": "skill-amp.md",
       "skill_dst": Path(".amp") / "skills" / "graphify" / "SKILL.md",
       "claude_md": False,
   },

   elif cmd in ("aider", "amp", "codex", "opencode", "claw", "droid", "trae", "trae-cn", "hermes"):

3. pyproject.toml — skill-amp.md added to [tool.setuptools.package-data] so the wheel ships it.

Both review bugs are fixed

1. ✅ skill-amp.md is now in pyproject.toml package-data — the installed wheel will include it, so graphify amp install no longer raises FileNotFoundError.
2. ✅ Install path is ~/.amp/skills/graphify/SKILL.md — matches the PR description from feat: add Amp (ampcode.com) as a supported platform #790 and avoids the collision with Codex / Antigravity at ~/.agents/skills/.

Verified on Windows

PS> python -m graphify install --platform amp
  skill installed  ->  C:\Users\danie\...\.amp\skills\graphify\SKILL.md
  Done.

PS> python -m graphify amp install
graphify section written to ...\AGENTS.md
Amp will now check the knowledge graph before answering
codebase questions and rebuild it after code changes.

PS> python -m graphify amp uninstall
AGENTS.md was empty after removal - deleted ...\AGENTS.md

Closes #790's review concerns.

[safishamsi]

Implemented in v8 (commit 80301a0) — graphify amp install/uninstall is now wired up with the correct .amp/skills/graphify/SKILL.md path, skill-amp.md included in package data, and the platform entry added to _PLATFORM_CONFIG. Thanks for the careful resubmission and the Windows verification!

[zuwasi]

Hi Safi,

Thanks for implementing Amp platform support in v8 — it's great to see it shipped and actively maintained. I'm glad the scoped resubmission was useful.

I wanted to kindly flag one thing: it looks like the Amp support that landed in commit 80301a06 was based on the work from this PR, but since the PR was closed without a merge commit, my authorship isn't preserved in the Git history. The commit is authored as Safi rather than crediting me as co-author.

The evidence linking the two:

• PR feat: add Amp (ampcode.com) as a supported platform (scoped resubmission of #790) #948 is explicitly referenced in the commit message (#948)
• The skill-amp.md file in 80301a06 has the same Git blob SHA (2aba0bacb1dbc706dc742ecd246906dfae32acc8) as the file I submitted in this PR — byte-for-byte identical
• The .agents/skills/graphify/SKILL.md install path originated in my follow-up commit 8f6f692 on this branch
• This PR predates the upstream landing by about a week (opened May 20, landed May 27)

I completely understand that squashing is normal workflow — I'm not asking to change the merge process. I'd just appreciate it if my contribution could be acknowledged, either by:

1. Adding a Co-authored-by: zuwasi <zuwasi@users.noreply.github.com> trailer to the commit (via git commit --amend or git rebase --exec), or
2. Adding me to the contributor credits in the README or a CONTRIBUTORS file

Either would be appreciated. No pressure either way — happy to have contributed something that made it into the project. Thanks again for maintaining Graphify!

Best,
zuwasi