chore(ci): replace SourceKnight with setup-sp

[Rushaway]

Summary

Replaces the SourceKnight-based build (maxime1907/action-sourceknight) with a native GitHub Actions workflow that clones dependencies directly and compiles with rumblefrog/setup-sp, following the pattern already validated in srcdslab/sm-plugin-AdminRoom.

Plugin targets

Target	Source file	Output
ConnectAnnounce	addons/sourcemod/scripting/ConnectAnnounce.sp	addons/sourcemod/plugins/ConnectAnnounce.smx

Dependencies

Name	Repo	Unpack path used (from sourceknight.yaml)
multicolors	https://github.com/srcdslab/sm-plugin-MultiColors	/addons → /addons (include copied to addons/sourcemod/scripting/include)
PlayerManager	https://github.com/srcdslab/sm-plugin-PlayerManager	/addons → /addons (include copied to addons/sourcemod/scripting/include)
sourcebans-pp	https://github.com/srcdslab/sourcebans-pp	game/addons/sourcemod/scripting/include → /addons/sourcemod/scripting/include
EntWatch	https://github.com/srcdslab/sm-plugin-EntWatch	/addons → /addons (include copied to addons/sourcemod/scripting/include)
KnockbackRestrict	https://github.com/srcdslab/sm-plugin-KnockbackRestrict	/addons → /addons (include copied to addons/sourcemod/scripting/include)

Note: sourcemod (type: tar) was skipped, as expected — SourceMod itself is provided by rumblefrog/setup-sp@v1.3.1 with version pinned to 1.12.x.

Packaging

The old workflow packaged .sourceknight/package/* plus the root common/ folder. The new Create package step replicates this using real, existing paths in the repo tree: it copies the compiled .smx into addons/sourcemod/plugins/ and copies the root common/ directory (which contains common/addons/sourcemod/configs/connect_announce/*.cfg) into the package root.

Not locally validated

No local spcomp run or dependency clone was performed as part of this change — paths were taken as declared in sourceknight.yaml and cross-checked against the repo's file tree only. The GitHub Actions run on this PR is the real signal for whether the build succeeds.

Manual verification needed

• Confirm the compiled build succeeds in CI (dependency include paths were derived from sourceknight.yaml declarations, not verified by cloning).
• Confirm the packaged artifact (.smx + common/) matches what downstream consumers expect; the previous packaging step used .sourceknight/package/* which may have included additional generated files not captured by this straightforward copy.

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