chore: bootstrap repo with chunks 1 and 2

Establishes the global AI development config repo from scratch:

- Chunk 1: repo skeleton, install.sh, statusline, deploy manifest
- Chunk 2: core instructions (coding/git/testing), CLAUDE.md rewrite
  (always-on + content index two-tier model), docs restructure,
  6 ADRs, ROADMAP.md, .gitkeep placeholders
- Bootstrap skills in .claude/skills/ (to be catalogued and migrated
  to .agents/skills/ in Chunk 3)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/grill-me/SKILL.md

@@ -0,0 +1,10 @@
+---
+name: grill-me
+description: Interview the user relentlessly about a plan or design until reaching shared understanding, resolving each branch of the decision tree. Use when user wants to stress-test a plan, get grilled on their design, or mentions "grill me".
+---
+
+Interview me relentlessly about every aspect of this plan until we reach a shared understanding. Walk down each branch of the design tree, resolving dependencies between decisions one-by-one. For each question, provide your recommended answer.
+
+Ask the questions one at a time.
+
+If a question can be answered by exploring the codebase, explore the codebase instead.