docs: simplify install section

Make the README install flow easier to scan by surfacing one-agent install paths directly and pointing users to `INSTALL.md` for the full matrix. Also ignore the local `tmp-starcharts/` scratch directory so generated chart work stays out of git.

Author: JuliusBrussee

.gitignore

@@ -12,3 +12,6 @@ context/refs/research-brief-caveman-code-efficiency.md
 # Build artifacts
 dist/*
 !dist/caveman.skill
+
+# Local star-history chart scratch (not part of the product)
+tmp-starcharts/

README.md

@@ -101,15 +101,7 @@ irm https://raw.githubusercontent.com/JuliusBrussee/caveman/main/install.ps1 | i
 
 ~30 seconds. Needs Node ≥18. Skips agents you no have. Safe to re-run.
 
-> [!TIP]
-> **Turn it on:** type `/caveman` or say *"talk like caveman"*. **Turn it off:** say *"normal mode"*. On Claude Code, Codex, and Gemini it's already on from message one. No command needed.
-
-<details>
-<summary><strong>Install for one agent, or any of 30+ others</strong></summary>
-
-<br>
-
-Every agent has its own path (plugin, extension, rule file, or `npx skills add`). The full per-agent matrix, all flags, dry-run, and uninstall live in **[INSTALL.md](./INSTALL.md)**. A few common ones:
+Prefer one agent at a time? Each has its own path:
 
 ```bash
 # Claude Code plugin
@@ -122,9 +114,12 @@ gemini extensions install https://github.com/JuliusBrussee/caveman --consent
 npx skills add JuliusBrussee/caveman -a cursor
 ```
 
-**Install broke?** Open your agent in this repo and say: *"Read CLAUDE.md and INSTALL.md, install caveman for me."* Agent read repo, agent fix own brain. Snake eat tail.
+The full per-agent matrix, all flags, dry-run, and uninstall live in **[INSTALL.md](./INSTALL.md)**.
 
-</details>
+> [!TIP]
+> **Turn it on:** type `/caveman` or say *"talk like caveman"*. **Turn it off:** say *"normal mode"*. On Claude Code, Codex, and Gemini it's already on from message one. No command needed.
+
+**Install broke?** Open your agent in this repo and say: *"Read CLAUDE.md and INSTALL.md, install caveman for me."* Agent read repo, agent fix own brain. Snake eat tail.
 
 ## Pick your grunt