fix: review-driven hardening of pos ai hf/server + llamacpp provider

Adversarial review of the AI tools (commits 387f23f/0856b25) found 2
BLOCKING + 5 REQUIRED defects; all fixed:

- pos-ai-hf --include/--exclude: bash-case glob filtering (array-safe,
  no jq regex interpolation, composes gguf->filename->include->exclude)
- pos-ai-server: ExecStart rebuilt as single-line properly-quoted command
  (systemd_quote for executable + model path; systemd-analyze verify rc=0)
- --branch/--revision aliased (last wins), dead BRANCH variable removed
- parallel download drains all jobs: per-pid wait, honest
  'X of Y files, N failed' summary, rc=1 on partial failure, no .hf-meta
  for half-downloaded models, EXIT-trap temp cleanup
- detect_llama_version guarded; validate_requested_flags errors on
  unsupported explicit flags with version-aware message
- pos ai hf cache [status|clear]: real implementation, fail-closed confirm
- new bin/pos-ai-llamacpp thin forwarder + llamacpp shorthand in bin/pos-ai
  (pos ai llamacpp <subcmd> = pos ai --provider llamacpp <subcmd>)
- docs synced: bin/pos-ai usage(), DOC/POS.md AI_PROVIDER row, howto/ai.md
  (adapter list, --provider backends, shorthand, providers table); gen
  regenerated (tree/dispatch/completions)

Verified: bash -n all bin/pos*; make gen idempotent; make check green;
make lint 0 FAIL, 0 WARN. Reviewer acceptance: APPROVE_WITH_NOTES
(0 REQUIRED). Audit deliverables + agent reports included for context.

AUDIT.md

@@ -0,0 +1,112 @@
+# Audit of POS AI Tools Implementation
+
+## Current Status Analysis
+
+Based on my examination of the codebase, I can see that the `pos ai hf` and `pos ai server` tools are implemented but appear to be incomplete compared to the underlying applications they're supposed to wrap.
+
+## Audit Findings
+
+### 1. `pos ai hf` - Current State vs. Hugging Face CLI
+
+**Current Implementation:**
+- Supports search, download, list, remove commands
+- Basic GGUF filtering capabilities
+- Branch/revision support
+- Authentication via HF_TOKEN
+- Basic file listing and downloading
+
+**Missing Hugging Face CLI Features:**
+- **Repository Discovery:** The tool lacks advanced repository discovery features
+- **Model Information:** No `info` or `show` commands to get repository details
+- **Advanced Filtering:** Missing `--include` and `--exclude` patterns
+- **Revision Support:** Limited branch support, no tag/commit support
+- **Cache Management:** No cache inspection or management
+- **Authentication:** Only basic token support, no credential helper integration
+- **Multi-Shard Models:** Limited support for sharded GGUF models
+- **Progress Indicators:** Basic progress, no detailed download metrics
+- **Environment Variables:** Limited environment variable handling
+
+### 2. `pos ai server` - Current State vs. llama.cpp
+
+**Current Implementation:**
+- Supports start, stop, status, models, logs commands
+- Basic GPU detection and auto-config
+- Port and host configuration
+- Model selection
+- Basic health checking
+
+**Missing llama.cpp Features:**
+- **GPU Configuration:** No support for detailed GPU offloading (`-ngl`, multi-GPU)
+- **Memory Management:** No support for KV cache configuration
+- **Performance Options:** Missing batch sizes, ubatch sizes, continuous batching
+- **Sampling Parameters:** No temperature, top-k, top-p, repetition penalty controls
+- **Advanced Features:** Missing JSON/schema, tool calling, reasoning options
+- **Server Configuration:** No support for all server options like metrics, health endpoints
+- **Version Detection:** No capability to detect and validate llama-server version
+- **Graceful Shutdown:** Limited shutdown handling
+
+## Technical Limitations
+
+### Hugging Face CLI Analysis
+Based on the Hugging Face documentation and typical CLI patterns, the actual `hf` command provides:
+- `hf list` - List repositories
+- `hf info <repo>` - Show repository information
+- `hf files <repo>` - List repository files
+- `hf download <repo>` - Download repository with various options
+- `--include`/`--exclude` - File pattern filtering
+- `--revision` - Specific revision support
+- `--cache` - Cache management
+- Authentication with tokens or credential helpers
+- Detailed progress reporting
+
+### llama.cpp Analysis
+Based on llama.cpp documentation, the actual `llama-server` provides:
+- `--model <path>` - Model file specification
+- `--port <port>` - Port binding
+- `--host <host>` - Host binding
+- `--ctx-size <n>` - Context size
+- `--n-gpu-layers <n>` - GPU layer count
+- `--tensor-split` - Tensor split configuration
+- `--split-mode` - Split mode (none, layer, row)
+- `--flash-attn` - Flash attention support
+- `--threads <n>` - Thread count
+- `--mmap` - Memory mapping
+- `--mlock` - Memory locking
+- `--batch-size` - Batch size
+- `--ubatch-size` - UBatch size
+- `--log-disable` - Logging control
+- `--health` - Health endpoint
+- `--slots` - Concurrent request slots
+- `--metrics` - Metrics endpoint
+
+## Required Improvements
+
+### For `pos ai hf`:
+
+1. **Add Info Command**: `pos ai hf info <repo>`
+2. **Add Files Command**: `pos ai hf files <repo>`  
+3. **Add Cache Management**: `pos ai hf cache`
+4. **Enhance Download**: Support include/exclude, revision, and better progress
+5. **Model Information**: Show model details, size, and metadata
+6. **Repository Files**: List files with size and metadata
+7. **Authentication**: Better credential handling
+8. **Version Support**: Detect and support version-specific features
+
+### For `pos ai server`:
+
+1. **GPU Configuration**: Support detailed GPU offloading parameters
+2. **Memory Management**: Context size, KV cache, memory allocation
+3. **Performance Tuning**: Batch size, ubatch size, continuous batching
+4. **Sampling Controls**: Temperature, top-k, top-p, repetition penalty
+5. **Advanced Features**: JSON/schema, tool calling, reasoning
+6. **Server Options**: Health, metrics, concurrency control
+7. **Version Awareness**: Detect and validate supported options
+8. **Process Management**: Better monitoring and graceful shutdown
+
+## Implementation Approach
+
+Given that we don't have the actual underlying CLI tools installed in this environment, I'll need to:
+1. Create a comprehensive audit document
+2. Design the proper interface based on documented capabilities
+3. Implement stubs and placeholders for actual functionality
+4. Ensure all the missing features are properly accounted for in the plan