skill: add Android skills

.agents/skills/appfunctions/references/kdoc-refinement-optimization.md

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+Optimizes AppFunction KDoc for AI agents and Model Context Protocol.
+
+## Instructions
+
+### Workflow: Agent-Centric Documentation
+
+1. **Identify the Core Outcome** : Start the description with a strong, imperative verb (e.g., "Search", "Create", "Update"). Focus on the *user
+   benefit*, not the code implementation.
+2. **Workflow Dependencies** : Explicitly state if another function must be called first using the standard phrase: **Required workflow: Call "Function
+   A" first to "Objective"**.
+3. **Parameter Documentation** :
+   - For **Functions** : Use specific `@param` tags. Isolate validation rules and default values here.
+   - For **Serializables** : Use inline KDoc directly for each property declarations. KSP will **not** extract documentation from class-level tags.
+4. **Error Surface Mapping** : Rewrite `@throws` descriptions to provide actionable recovery steps for the AI agent (e.g., "If "Error", suggest the user check their internet connection").
+
+### Workflow: Global App Description (Server Instructions)
+
+When writing the `appfn:description` for `app_metadata.xml`, follow these
+instructions:
+
+1. **Capture Cross-Function Relationships**: Explain dependencies or sequences between tools (e.g., "Always call 'authenticate' before fetching data").
+2. **Document Operational Patterns**: Guide the LLM on token conserving usage (e.g., "Use 'batch_update' over multiple 'update' calls").
+3. **Specify Constraints**: Define clear boundaries (e.g., "File operations limited to workspace", "Rate limit: 10 req/min").
+4. **Anti-Patterns** :
+   - DON'T repeat individual function descriptions.
+   - DON'T include marketing claims or subjective praise.
+   - DON'T attempt to prompt model personality or conversation style.
+
+## Critical Constraints
+
+### Descriptive, Not Imperative
+
+Describe what the function *does* , not what the LLM *must* do. Avoid phrases
+like "You must call this..." in favor of "This function provides...".
+
+### No "Fluff"
+
+Remove conversational padding like "This method is used to..." or "Helpful
+for...". Be concise and technical.
+
+### Inline KDoc for Serializables
+
+**MANDATORY** : For `@AppFunctionSerializable` classes, documentation MUST be
+inline For each property. KSP ignores class-level `@param` or `@property` tags
+for these classes.
+
+## Examples
+
+### Example: MCP Refactoring
+
+**Original**:
+
+`/** This function helps you find people. */`
+
+**Refined**:
+
+    /**
+      * Search for message recipients by name or email.
+      * Required workflow: Call this before "sendMessage" to obtain valid recipient IDs.
+      * @param query Search string for name/email. If null, returns 3 most recent contacts.
+      * @return List of "Recipient" objects matching the query.
+      */
+
+### Example: Global App Description
+
+**Refined**:
+
+    This app provides functions for task management and team collaboration.
+
+    Operational Patterns:
+      - Always use 'searchUsers' to resolve user handles to internal IDs before calling 'assignTask'.
+      - Prefer 'batchUpdateStatus' when modifying more than 3 tasks simultaneously to reduce
+    latency.
+
+    Constraints:
+      - Task titles are limited to 100 characters.
+      - Attachment uploads are limited to 5MB.