feat: template-based dual-target generator for Claude + Codex

Replace generate-codex.sh with unified generate.sh that produces both
claude/ and codex/ output from template source files.

Agent bodies use ${PLANS_DIR}, ${WEB_SEARCH}, ${SEARCH_TOOLS} placeholders
expanded per-target via envsubst. Skills and rules made tool-agnostic
(no Claude tool names or .claude/ paths). Orchestrate skill stays
Claude-only.

install.sh now symlinks from claude/agents/ instead of agents/ directly.
flake.nix adds gettext (envsubst) to devShell.

skills/message-schema/SKILL.md

@@ -151,7 +151,7 @@ Emitted by: architect (Phase 2)
 ---
 type: plan_result
 signal: plan_complete | blocked
-plan_file: .claude/plans/kebab-case-title.md
+plan_file: plans/kebab-case-title.md
 wave_count: 3
 step_count: 7
 risk_tags:
@@ -202,7 +202,7 @@ Sent to: worker, debugger, documenter
 type: task_assignment
 signal: execute
 task: "short task title"
-plan_file: .claude/plans/kebab-case-title.md
+plan_file: plans/kebab-case-title.md
 wave: 1
 step: 2
 ---

skills/project/SKILL.md

@@ -4,7 +4,7 @@ description: Instructs agents to check for and ingest a project-specific skill f
 when_to_use: Loaded by all agents. Checks for .claude/skills/project.md in the working directory and ingests project-local conventions.
 ---
 
-Before starting any work, check for a project-specific skill file at `.claude/skills/project.md` in the current working directory.
+Before starting any work, check for a project-specific skill file in the current working directory's configuration.
 
 If it exists, read it and treat its contents as additional instructions — project conventions, architecture notes, domain context, or anything else the project maintainer has defined. These instructions take precedence over general defaults where they conflict.
 

skills/qa-checklist/SKILL.md

@@ -9,7 +9,7 @@ when_to_use: Loaded by all agents that produce output envelopes. Run before retu
 Before returning your output, validate against every item below. If you find a violation, fix it — don't just note it.
 
 ### Factual accuracy
-- Every file path, function name, class name, and line number you reference — does it actually exist? Verify with Read/Grep if uncertain. Never guess paths or signatures.
+- Every file path, function name, class name, and line number you reference — does it actually exist? Verify by reading the code if uncertain. Never guess paths or signatures.
 - Every version number, API endpoint, or external reference — is it correct? If you can't verify, say "unverified" explicitly.
 - No invented specifics. If you don't know something, say so.
 

skills/worker-protocol/SKILL.md

@@ -47,7 +47,7 @@ Before returning your output, run the `qa-checklist` skill against your work. Fi
 ## Cost sensitivity
 
 - Keep responses tight. Result only.
-- Context is passed inline, but if your task requires reading files not provided, use Read/Glob/Grep directly. Don't guess at file contents — verify. Keep it targeted.
+- Context is passed inline, but if your task requires reading files not provided, verify by reading the relevant files. Don't guess at file contents. Keep it targeted.
 
 ## Commits