Add comprehensive workflows for CLI tools usage, coding philosophy, context requirements, file modification, and CodexLens auto hybrid mode

- Introduced a detailed guide for intelligent tools selection strategy, including quick reference, tool specifications, prompt templates, and best practices for CLI execution.
- Established a coding philosophy document outlining core beliefs, simplicity principles, and guidelines for effective coding practices.
- Created context requirements documentation emphasizing the importance of understanding existing patterns and dependencies before implementation.
- Developed a file modification workflow detailing the use of edit_file and write_file MCP tools, along with priority logic for file reading and editing.
- Implemented CodexLens auto hybrid mode, enhancing the CLI with automatic vector embedding generation and default hybrid search mode based on embedding availability.

.claude/workflows/file-modification.md

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+## File Modification
+
+### Use edit_file (MCP)
+- Built-in Edit tool failed 1+ times
+- Need dry-run preview before applying changes
+- Need line-based operations (insert_after, insert_before)
+- Need to replace all occurrences at once
+- Built-in Edit returns "old_string not found"
+- Whitespace/formatting issues in built-in Edit
+
+**Mode Selection**:
+- `mode=update`: Replace text
+- `mode=line`: Line-based operations
+
+### Use write_file (MCP)
+- Creating brand new files
+- MCP edit_file still fails (last resort)
+- Need to completely replace file content
+- Need backup before overwriting
+- User explicitly asks to "recreate file"
+
+## Priority Logic
+
+**File Reading**:
+1. Known single file → Built-in Read
+2. Multiple files OR pattern matching → read_file (MCP)
+3. Unknown location → smart_search then Read
+4. Large codebase + repeated access → codex_lens
+
+**File Editing**:
+1. Always try built-in Edit first
+2. Fails 1+ times → edit_file (MCP)
+3. Still fails → write_file (MCP)
+
+**Search**:
+1. External knowledge → Exa
+2. Exact pattern in small codebase → Built-in Grep
+3. Semantic/unknown location → smart_search
+4. Large codebase + repeated searches → codex_lens
+
+## Decision Triggers
+
+**Start with simplest tool** (Read, Edit, Grep)
+**Escalate to MCP tools** when built-ins fail or inappropriate
+**Use semantic search** for exploratory tasks
+**Use indexed search** for large, stable codebases
+**Use Exa** for external/public knowledge
+
+## ⚡ Core Search Tools
+
+**rg (ripgrep)**: Fast content search with regex support
+**find**: File/directory location by name patterns
+**grep**: Built-in pattern matching (fallback when rg unavailable)
+**get_modules_by_depth**: Program architecture analysis (MANDATORY before planning)
+
+
+## 🔧 Quick Command Reference
+
+```bash
+# Semantic File Discovery (codebase-retrieval via CCW)
+ccw cli exec "
+PURPOSE: Discover files relevant to task/feature
+TASK: • List all files related to [task/feature description]
+MODE: analysis
+CONTEXT: @**/*
+EXPECTED: Relevant file paths with relevance explanation
+RULES: Focus on direct relevance to task requirements | analysis=READ-ONLY
+" --tool gemini --cd [directory]
+
+# Program Architecture (MANDATORY before planning)
+ccw tool exec get_modules_by_depth '{}'
+
+# Content Search (rg preferred)
+rg "pattern" --type js -n        # Search JS files with line numbers
+rg -i "case-insensitive"         # Ignore case
+rg -C 3 "context"                # Show 3 lines before/after
+
+# File Search
+find . -name "*.ts" -type f      # Find TypeScript files
+find . -path "*/node_modules" -prune -o -name "*.js" -print
+
+# Workflow Examples
+rg "IMPL-\d+" .workflow/ --type json                    # Find task IDs
+find .workflow/ -name "*.json" -path "*/.task/*"        # Locate task files
+rg "status.*pending" .workflow/.task/                   # Find pending tasks
+```
+
+## ⚡ Performance Tips
+
+- **rg > grep** for content search
+- **Use --type filters** to limit file types
+- **Exclude dirs**: `--glob '!node_modules'`
+- **Use -F** for literal strings (no regex)