feat(skills): import core skills from .agents catalog

- Add junior-to-senior with research playbook and review rubric
- Add fuck-slop with tell catalog and multi-register voice profiles
- Add interface-kit with design engineering, motion, and a11y references
- Add app-security with 4-pillar upload defense and hardening playbooks
- Add debugging-workflow with systematic root cause isolation
- Standardize all skills to 5-phase Skill Architect protocol
- Sync symlinks to OpenCode, Codex, and Claude Code

skills/app-security/SKILL.md

@@ -0,0 +1,98 @@
+---
+name: app-security
+description: >
+  Full-stack application and API security hardening: Four-Pillar upload defense,
+  SSRF prevention, input boundary clamping, IDOR elimination, and secret masking.
+  Use when creating or auditing API routes, handling uploads, making outbound requests,
+  or preparing pre-release security verification.
+concerns: [security]
+---
+
+# Application Security Hardening
+
+Enforces defensive boundaries across the API membrane, eliminating exploit vectors, path traversals, SSRF risks, IDOR vulnerabilities, and payload exhaustion.
+
+```mermaid
+flowchart LR
+    A["Inbound Request"] --> B["1. Membrane Clamping<br/>(Schema & Bound Validation)"]
+    B --> C["2. Four-Pillar Uploads<br/>(Size, Ext, Magic, Path)"]
+    C --> D["3. Outbound SSRF Guard<br/>(Loopback/Metadata Block)"]
+    D --> E["4. Secret Masking<br/>(Zero Token Sediment)"]
+```
+
+---
+
+## Phase 0: Setup and Protocols
+
+1. Review reference playbooks:
+   - [references/app-hardening-playbook.md](references/app-hardening-playbook.md) for concrete TypeScript/Python code patterns and boundary clamps.
+   - [references/review-checklist.md](references/review-checklist.md) for pre-release OWASP verification checks.
+2. Invariants:
+   - Every input payload must be typed and bounded.
+   - Every state mutation must verify session identity and tenant ownership.
+   - Outbound HTTP fetches must never touch private/loopback networks.
+
+---
+
+## Phase 1: Ingest and Check
+
+1. **Surface Identification**:
+   - Inbound API routes (REST, GraphQL, RPC handlers).
+   - File/document ingestion and attachment endpoints.
+   - Outbound network calls (webhooks, URL unfurlers, external data scrapers).
+   - Data persistence operations and logging sinks.
+2. **Access Control Check**:
+   - Confirm identity is derived from verified server sessions/tokens, never trusted client parameters (`userId`, `orgId`).
+   - Confirm entity queries enforce ownership: verify record exists AND belongs to the authenticated caller before mutating.
+
+---
+
+## Phase 2: Processing (Core Logic)
+
+### Step 1: Input Boundaries & Membrane Clamping
+- Never accept arbitrary, unvalidated request dictionaries. Model all payloads using strict schemas (e.g. Pydantic, Zod).
+- Enforce hard string limits:
+  - Text prompts / message content: Max 50,000 characters.
+  - Titles / Names: Max 100–200 characters.
+  - Pagination limits: Clamped to `1 <= limit <= 50`.
+  - Batch arrays: Clamped to max 100–200 items.
+- Sanitize entity and path identifiers against path traversal tokens (`../`, `..\\`).
+
+### Step 2: Four-Pillar Upload Defense
+When handling file or media uploads:
+1. **Size Bounds**: Reject payloads exceeding size thresholds (e.g., 100MB for docs; 5MB for images).
+2. **Blocked Extensions**: Reject executable and script formats (`.exe`, `.bat`, `.sh`, `.svg`, `.html`, `.php`).
+3. **Magic Byte Inspection**: Inspect file headers to detect disguised binaries (PE `MZ`, ELF, Mach-O).
+4. **Path Traversal Defense**:
+   - Sanitize original filenames (strip path separators and non-printable characters).
+   - Write files strictly to designated, isolated upload roots with unique IDs (e.g. UUID filenames).
+
+### Step 3: Outbound SSRF Guard
+Before executing outbound HTTP requests (scraping, webhooks):
+- Validate target URLs against an allowlist or safety filter.
+- Block loopback addresses (`127.0.0.1`, `localhost`, `::1`), RFC 1918 private subnets (`10.0.0.0/8`, `172.16.0.0/12`, `192.168.0.0/16`), and cloud metadata services (`169.254.169.254`).
+- Restrict allowed protocols strictly to `http` and `https`.
+
+### Step 4: Secret Masking & Error Shielding
+- Scrub Authorization tokens (`Bearer ***`), provider API keys, and sensitive credentials from logs, database traces, and telemetry.
+- In public HTTP error responses, return clean structured error objects with opaque error codes; never leak internal filesystem paths, environment variables, or stack traces.
+
+---
+
+## Phase 3: The System One Balance Pass
+
+- **Augment, Don't Handcuff**:
+  - Do NOT break local development workflows: allow local mock endpoints and fixture testing in non-production test environments.
+  - Keep security checks non-intrusive during prototyping; enforce strictly at boundaries and pre-release gates.
+  - Avoid noisy confirmation warnings for routine safe operations.
+
+---
+
+## Phase 4: Output Execution & Verification
+
+1. Run verification checks from [references/review-checklist.md](references/review-checklist.md).
+2. Provide a security verification summary detailing:
+   - Bound clamps applied to route schemas.
+   - Upload filters active (size, extension, magic bytes, safe path).
+   - SSRF protection status on outbound calls.
+   - Secret scrubbing confirmation.