chore: merge main, resolve biome formatting conflicts

Merge origin/main into feat/external-2fa-codes. Resolve formatting
conflicts caused by biome rollout; preserve both feature streams:
PR's external 2FA token + signing-session 2FA proof additions plus
main's RateLimit/RecipientExpired/signingReminders/date-auto-insert.

In complete-document-with-token.ts, drop the duplicate early
field-fetching block introduced when main moved that logic later
with date auto-insert support; keep the EXTERNAL_TWO_FACTOR_AUTH
check using derivedRecipientActionAuth.

.opencode/commands/create-plan.md

@@ -7,70 +7,17 @@ You are creating a new plan file in the `.agents/plans/` directory.
 
 ## Your Task
 
-1. **Determine the slug** - Use `$ARGUMENTS` as the file slug (kebab-case recommended)
-2. **Gather content** - Collect or generate the plan content
-3. **Create the file** - Use the create-plan script to generate the file
+Load and follow the skill at `.agents/skills/create-plan/SKILL.md`. It contains the complete instructions for creating plan files including:
 
-## Usage
+- Unique three-word ID generation
+- Frontmatter format with date and title
+- Script usage (`scripts/create-plan.ts`)
 
-The script will automatically:
+## Context
 
-- Generate a unique three-word ID (e.g., `happy-blue-moon`)
-- Create frontmatter with current date and formatted title
-- Save the file as `{id}-{slug}.md` in `.agents/plans/`
-
-## Creating the File
-
-### Option 1: Direct Content
-
-If you have the content ready, run:
-
-```bash
-npx tsx scripts/create-plan.ts "$ARGUMENTS" "Your plan content here"
-```
-
-### Option 2: Multi-line Content (Heredoc)
-
-For multi-line content, use heredoc:
-
-```bash
-npx tsx scripts/create-plan.ts "$ARGUMENTS" << HEREDOC
-Your multi-line
-plan content
-goes here
-HEREDOC
-```
-
-### Option 3: Pipe Content
-
-You can also pipe content:
-
-```bash
-echo "Your content" | npx tsx scripts/create-plan.ts "$ARGUMENTS"
-```
-
-## File Format
-
-The created file will have:
-
-```markdown
----
-date: 2026-01-13
-title: Plan Title
----
-
-Your content here
-```
-
-The title is automatically formatted from the slug (e.g., `my-feature` → `My Feature`).
-
-## Guidelines
-
-- Use descriptive slugs in kebab-case (e.g., `user-authentication`, `api-integration`)
-- Include clear, actionable plan content
-- The unique ID ensures no filename conflicts
-- Files are automatically dated for organization
+The plan slug and optional content: `$ARGUMENTS`
 
 ## Begin
 
-Create a plan file using the slug from `$ARGUMENTS` and appropriate content for the planning task.
+1. **Read the skill** at `.agents/skills/create-plan/SKILL.md`
+2. **Create the plan file** using the slug from `$ARGUMENTS` and appropriate content