docs: add comprehensive CLI command reference (closes #65)

[DsThakurRawat]

Description

Creates a comprehensive docs/cli_reference.md to document every reflex CLI command. This resolves the issue of users needing to run --help repeatedly.

Key Additions:

• Top-Level Commands: Full documentation for go, serve, ros2-serve, export, validate, doctor, guard, bench, models, and chat.
• Flag Details: Exhaustive tables detailing default values and descriptions for every flag.
• Examples: Practical bash examples for typical use cases.
• Vertical Quick-Start Matrix: A quick-reference guide tailoring commands for specific deployments:
  • Warehouse robotics (AGVs, arms)
  • Farm robotics (outdoor arms)
  • Aerial drones (UAVs)
  • Retail loss prevention (cameras)
  • Traffic AI management

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Infrastructure / CI update

How Has This Been Tested?

• pytest tests/ passes locally
• reflex doctor sanity check
• Other (please specify): Verified formatting and cross-referenced with codebase/schema.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have kept the PR scoped to a single concern (one concern per PR)

[rylinjames]

Thanks @DsThakurRawat — the structure of this reference (orientation → per-verb sections → vertical matrix → env vars) is solid. I want to credit you for that. I've opened a consolidated, source-audited replacement. You're credited via Co-Authored-By on the commit so it lands in your contribution graph.

Key differences from this PR:

1. Dropped reflex turbo — source at cli.py:2385 says it's deprecated and prints a banner pointing to reflex serve --adaptive-steps. Same for split and adapt.
2. Dropped bench, validate-dataset, and other hidden internal verbs from the user-facing list. They're still callable, just not in the discovery surface.
3. ros2-serve moved to an "Advanced commands" section with a "hidden from --help but production-supported" caveat, and the new --state-msg-type flag from fix(ros2): pluggable state extractors (joint_state / imu / odom) #133 added to its flag table.
4. Restored the vertical matrix I had initially planned to drop. Cross-checked against 02_research/customers/MASTER.md in the FastCrest research vault — traffic-management, retail, smart-camera warehouse, drone surveillance are all explicit P0 customer subcategories with 12-13/15 composite scores. The matrix in the replacement PR now mirrors the vault's top 11 P0 picks.
5. Trimmed flag tables to verified key flags only. Every section ends with Full flag list: reflex <verb> --help so the doc can't drift from source.

Closing in favor of the replacement PR. Please keep contributing!