Sync lockfile self-version to 0.104.0 and track it in .codegen.json (#770)

## Summary

Fixes the `check-lock` CI job, which has been failing on every PR since
the v0.104.0 release, and wires the lockfile self-version into
`.codegen.json` so the release bot keeps it in sync going forward.

**Net effective diff:**
- `lockfile.json`: `"version": "0.103.0"` → `"0.104.0"` (project
self-version stamp)
- `databricks-sdk-java/lockfile.json`: `"version": "0.103.0"` →
`"0.104.0"`, plus 91 `"resolved"` URLs normalized from the stale
`maven-proxy.dev.databricks.com` proxy back to
`repo.maven.apache.org/maven2` (checksums and selected versions
unchanged)
- `.codegen.json`: both `lockfile.json` entries added to the `version`
map so the release bot bumps the self-version stamp alongside the
pom.xml files at release time

## Why

Commit [c482384 "[Release] Release
v0.104.0"](c4823843)
bumped the project version in all 5 `pom.xml` files from `0.103.0` →
`0.104.0`, but did **not** update `lockfile.json` or
`databricks-sdk-java/lockfile.json`. Both still recorded `"version":
"0.103.0"` for the project's own GAV.

`mvn maven-lockfile:validate` was failing every PR with:

```
Your lockfile from file is for:     com.databricks:databricks-sdk-parent:0.103.0
Your generated lockfile is for:     com.databricks:databricks-sdk-parent:0.104.0
```

The release only bumped the self-version — no dependencies were added,
removed, or changed — so no transitive SHAs needed to change.

## How the regenerated lockfile was produced

Running `make lock` locally in a sandbox without JFrog OIDC credentials
isn't possible, so the regeneration was done inside CI on this branch
(where `setup-build-environment` provides OIDC-authenticated JFrog
access). Commits `5d376ce1` and `54e67137` on this branch are the
bootstrap + bot-generated regeneration; commit `bbc7fd7d` reverts the
bootstrap. The net effect is identical to what `make lock && make
fix-lockfile` would have produced locally.

## Prevention: `.codegen.json` update

Per Hector's suggestion, added both `lockfile.json` files to the
`version` map in `.codegen.json` with an anchor pattern of:

```
"artifactId": "<id>",\n  "groupId": "com.databricks",\n  "version": "$VERSION"
```

This ensures the release bot updates the self-version stamp in both
lockfiles on future releases, preventing this mismatch from recurring.

## User impact

None. `lockfile.json` is consumed only by `maven-lockfile:validate` in
CI; it is not published to Maven Central. The SDK artifacts downstream
consumers pull are unaffected.

## How is this tested

The PR's own `check-lock` job is the test — it should transition from
red to green. Verified green on the bot-regenerated commit `54e67137`.

## Commits on this branch (suggest squash-merge)

```
30ed03f Track lockfile version in .codegen.json
bbc7fd7 Remove temporary regenerate-lock CI job
54e6713 Regenerate lockfile via CI        ← by github-actions[bot]
5d376ce [TEMP] Add regenerate-lock CI job
0863613 Sync lockfile self-version to 0.104.0
```

---

`NO_CHANGELOG=true`

This pull request and its description were written by Isaac.

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: mihaimitrea-db

.codegen.json

@@ -7,7 +7,9 @@
     "databricks-sdk-java/src/main/java/com/databricks/sdk/core/UserAgent.java": "private static final String version = \"$VERSION\";",
     "examples/docs/pom.xml": "<artifactId>databricks-sdk-java</artifactId>\n      <version>$VERSION</version>",
     "examples/spring-boot-oauth-u2m-demo/pom.xml": "<artifactId>databricks-sdk-java</artifactId>\n      <version>$VERSION</version>",
-    "shaded/pom.xml": "<properties>\n    <sdk.version>$VERSION</sdk.version>"
+    "shaded/pom.xml": "<properties>\n    <sdk.version>$VERSION</sdk.version>",
+    "lockfile.json": "\"artifactId\": \"databricks-sdk-parent\",\n  \"groupId\": \"com.databricks\",\n  \"version\": \"$VERSION\"",
+    "databricks-sdk-java/lockfile.json": "\"artifactId\": \"databricks-sdk-java\",\n  \"groupId\": \"com.databricks\",\n  \"version\": \"$VERSION\""
   },
   "toolchain": {
     "require": ["mvn", "java"],