Add AGENTS.md on-ramp, response-style rules, and optional No-Fluff Mode

- AGENTS.md: auto-read session on-ramp — memory-map reading order, working
  rules, build command, and startup-log pointer
- ai.md: Response style section (no default planning boilerplate) plus an
  optional, on-demand No-Fluff Mode for ruthless review; never the default
- schema.md: AGENTS.md listed as the always-read first page

schema.md

@@ -16,6 +16,7 @@ that every other memory file follows. Read `ai.md` first; this file explains
 
 | File | Role | Entry point? |
 |------|------|--------------|
+| `AGENTS.md` | Auto-read on-ramp for AI sessions — points to the map and the working rules | **always read first** |
 | `README.md` | Human-facing intro: what the app is, how to run it, roadmap | no |
 | `ai.md` | **AI guide + session handoff** — architecture, patterns, decisions, the cognitive map home | **yes — start here** |
 | `TASKS.md` | Task queue + authoritative YouTube API research facts + task statuses | yes — for status |
@@ -42,10 +43,11 @@ that every other memory file follows. Read `ai.md` first; this file explains
 
 ## Reading order
 
-1. `ai.md` — what this app is, how it's built, current state, open decisions.
-2. `TASKS.md` — what's done, what's next, and the YouTube API constraints.
-3. `<dir>/index.md` — to understand a directory before reading its files.
-4. The source files themselves — always the authority over any memory file.
+1. `AGENTS.md` — auto-read on-ramp; it points you here.
+2. `ai.md` — what this app is, how it's built, current state, open decisions.
+3. `TASKS.md` — what's done, what's next, and the YouTube API constraints.
+4. `<dir>/index.md` — to understand a directory before reading its files.
+5. The source files themselves — always the authority over any memory file.
 
 ## Integration rule