Fix/release split by target (#24)

* feat(release): drop darwin_amd64 (Intel Macs)

Intel Macs are no longer receiving macOS updates. Drop from release
matrix and re-add to goreleaser ignore list. install.sh now prints
a clear message pointing Intel users to build-from-source. README
manual-install section no longer advertises a darwin_amd64 URL.

* feat: anonymous usage telemetry via oss-telemetry

Send a single fire-and-forget ping at startup to help track adoption
and version spread. No persistent identifiers are collected.

Also adds main.version var (defaulting to "dev") so the existing
goreleaser ldflags injection (-X main.version={{.Version}}) now binds
to a real symbol.

Opt out via any of:
  DO_NOT_TRACK=1
  OSS_TELEMETRY_DISABLED=1
  MCP_FILEPUFF_DISABLE_TELEMETRY=1

* docs: add Telemetry section linking to oss-telemetry opt-out docs

Discloses the single anonymous adoption ping sent on startup and points
users to the upstream README section for full opt-out instructions
instead of duplicating the table here.

README.md

@@ -844,6 +844,19 @@ Use the `ping` tool to verify the server is running correctly:
 
 Expected response: `"pong"`
 
+## Telemetry
+
+On startup this MCP server sends a single anonymous adoption ping — project
+name, version, timestamp; no identifiers, no tool call data, no file
+contents. Fire-and-forget with a 2-second timeout; cannot block startup
+or panic.
+
+See **[oss-telemetry — Disabling telemetry](https://github.com/lukaszraczylo/oss-telemetry#disabling-telemetry)**
+for the exact wire format, source, and full opt-out documentation.
+
+Quick opt-out: set any of `DO_NOT_TRACK=1`, `OSS_TELEMETRY_DISABLED=1`,
+or `MCP_FILEPUFF_DISABLE_TELEMETRY=1`.
+
 ## License
 
 MIT License