docs(install): correct how the guard reaches a consumer, measured both ways

The v0.4.0 release commit claimed the [tool.uv.sources] entry "never
reaches consumers". Measured against the pushed tag in clean
environments, that is wrong in one direction and understated in the
other:

- uv, installing this package from git, DOES pick the guard up from the
  tag automatically. uv reads pyproject.toml when it builds from the
  source tree, so the source applies to the consumer too, not just to
  development here.
- pip does not read it, and fails outright: "No matching distribution
  found for llm-ingestion-guard<0.3,>=0.2". The guard must be installed
  from its own tag FIRST. Verified that the guard-first order then
  installs cleanly and that the shipped adapter runs against the real
  guard in that environment.

What did hold is the part that matters for the pin: the built wheel
carries `Requires-Dist: llm-ingestion-guard<0.3,>=0.2`, so the range is
still the declared dependency and the git URL is still a channel.

README now states the pip order as the default instruction, with the uv
shortcut beside it, because a consumer hitting the resolution error would
otherwise read it as a broken release.

pyproject.toml

@@ -50,9 +50,14 @@ python_version = "3.10"
 module = ["llm_ingestion_guard", "llm_ingestion_guard.*"]
 ignore_missing_imports = true
 
-# Development-time install CHANNEL for the guard, which is not on a package
-# index yet. It resolves `uv lock`/`uv sync` against the tag; it is uv-specific
-# and never reaches consumers — the built wheel carries the range from
-# [project.dependencies] above, which is the pin.
+# Install CHANNEL for the guard, which is not on a package index yet. It is
+# uv-specific, and it reaches further than a dev-only setting: measured
+# 2026-07-25, a consumer installing this package from git WITH UV picks the
+# guard up from this tag automatically, because uv reads this file when it
+# builds from the source tree. pip does not read it — it resolves
+# [project.dependencies] alone and fails with "No matching distribution found
+# for llm-ingestion-guard" until the guard is installed from its own tag first
+# (README). Either way the range above stays the pin: the built wheel carries
+# `Requires-Dist: llm-ingestion-guard<0.3,>=0.2`, verified against the wheel.
 [tool.uv.sources]
 llm-ingestion-guard = { git = "https://git.fromaitochitta.com/open/llm-ingestion-pipeline-security.git", tag = "v0.2.0" }