[CHORE] The version string is duplicated across four files with no release checklist

[SakethSumanBathini]

0.2.0 currently appears in at least:

pyproject.toml:7          version = "0.2.0"
README.md:3               shields.io badge  (AgentWatch-v0.2.0)
README.md:474             "AgentWatch **v0.2.0** is being built now"
agentwatch/cli/demo.py:572  "AgentWatch - Demo Suite v0.2.0"

Four places, hand-maintained. Drift between package metadata, the README badge and what the CLI
prints is the kind of thing nobody notices until a user reports that agentwatch --version disagrees
with PyPI — and for a security tool, a version you can't trust is a small but real credibility cost.

Suggested fix

Two options, either is fine:

1. Single source of truth — read the version from package metadata
   (importlib.metadata.version("agentwatch")) in demo.py rather than hardcoding it, and use a
   dynamic shields.io endpoint for the badge. Then only pyproject.toml carries the number.
2. A release checklist in CONTRIBUTING listing every version-bearing file, so bumps stay atomic.

(1) removes the failure mode; (2) documents it. (1) is barely more work.