Add clear and concise logging with -v flag

[Copilot]

Implements clear and concise logging for the coding-context-cli tool with a -v/--verbose flag to control output verbosity.

Changes Made

• Added -v/--verbose flag: Controls logging verbosity
  • Default mode (no flag): Clean output with no log messages, suitable for piping to AI agents
  • Verbose mode (-v): Detailed INFO-level logs with timestamps showing progress
• Updated error handling: Error messages now use fmt.Fprintf instead of logger for clean, unformatted output
• Updated usage output: Usage information now uses fmt.Fprintln instead of logger for cleaner display
• Improved log messages: Made messages more concise and user-friendly
  • "Including rule file" → "Rule loaded" (with basename only)
  • "Including task" → "Task loaded"
  • "Total estimated tokens" → "Context assembled" (with additional details)
  • "Downloading remote directory" → "Downloading"
  • "Downloaded to" → "Downloaded"

Example Output

Without -v (default):

---
task_name: test-task
---
# Test Rule
# Test Task

With -v (verbose):

time=2025-12-24T00:58:10.477Z level=INFO msg="Using local directory" path=/tmp/test
time=2025-12-24T00:58:10.477Z level=INFO msg="Task loaded" tokens=8
time=2025-12-24T00:58:10.477Z level=INFO msg="Rule loaded" path=test-rule.md tokens=8
time=2025-12-24T00:58:10.478Z level=INFO msg="Context assembled" total_tokens=16 rules=1
---
task_name: test-task
---
# Test Rule
# Test Task

Testing

• ✅ All existing tests pass
• ✅ Linter passes
• ✅ Manual testing confirms both verbose and non-verbose modes work correctly
• ✅ CodeQL security scan shows no issues

Original prompt

Add clear and concise logging.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[alexec]

@copilot very nice, but maybe follow your original plan.

[Copilot]

@copilot very nice, but maybe follow your original plan.

Implemented the original plan in commit 2fca625. The changes include:

Without -v flag (default):

---
task_name: test-task
---
# Test Rule
This is a test rule.

# Test Task
This is a test task.

With -v flag (verbose):

time=2025-12-24T00:58:10.477Z level=INFO msg="Using local directory" path=/tmp/test-logging
time=2025-12-24T00:58:10.477Z level=INFO msg="Using local directory" path=/home/runner
time=2025-12-24T00:58:10.477Z level=INFO msg="Task loaded" tokens=8
time=2025-12-24T00:58:10.477Z level=INFO msg="Rule loaded" path=test-rule.md tokens=8
time=2025-12-24T00:58:10.478Z level=INFO msg="Context assembled" total_tokens=16 rules=1
---
task_name: test-task
---
# Test Rule
This is a test rule.

# Test Task
This is a test task.

Error messages are now clean without slog formatting, and usage output uses fmt instead of logger.