Promotes pending master commits to the OSS docs-release branch ahead
of the InfluxDB OSS 2.9.0 release. Includes #652 (Gzip-Compression-Level
parameter on /backup/shards/{shardID}) — the spec change backing the
backup gzip compression docs in influxdata/DAR#682.

Refs influxdata/DAR#682.

Add v2.9.0 release notes and supporting docs for the InfluxDB OSS
2.9.0 release.

Token hashing default change:
- Add v2.9.0 release notes section with "Before you upgrade" callout,
  disable / opt-out guidance, and backup/restore workflow note.
- Flip the use-hashed-tokens default in the config-options reference
  from false to true; rewrite intro and examples to reflect the new
  default.
- Add a Token hashing section to admin/tokens/ covering version
  defaults, startup behavior, opt-out, downgrade considerations, and
  recovery for lost tokens.
- Add a sitewide notification scoped to /influxdb/v2 and a cascade
  prepend on the /influxdb/v2 landing page that surface the change on
  every page in the v2 doc tree.
- Register --use-hashed-tokens in data/influxd_flags.yml so it
  appears in the influxd flag list.

Backup gzip compression:
- Document the new server-side Gzip-Compression-Level header and the
  influx backup --gzip-compression-level flag (influx-cli 2.8.0+) in
  the admin backup page and the shared CLI reference, including the
  --compression coupling.
- Note the regenerated v2 OpenAPI bundle in api-docs/, produced by
  api-docs/getswagger.sh after promoting influxdata/openapi#652 to
  docs-release/influxdb-oss. The /backup/metadata operation is still
  missing the parameter; tracked in influxdata/openapi#653.

Restore --operator-token:
- Document the new --operator-token flag (influx-cli 2.8.0+) in the
  admin restore page and the shared CLI reference, with explicit
  guidance for restoring backups whose operator token is hashed.

EDR replication:
- Note the new maxAgeSeconds bounds (60s–60d, 0 = use default) in the
  v2.9.0 release notes.

Version metadata:
- Bump data/products.yml: latest v2.8 -> v2.9, latest_patches.v2
  2.8.0 -> 2.9.0, latest_cli.v2 2.7.5 -> 2.8.0.

Refs influxdata/DAR#682

Add v2.9.0 release notes and supporting docs for the InfluxDB OSS
2.9.0 release.

Token hashing default change:
- Add v2.9.0 release notes section with "Before you upgrade" callout,
  disable / opt-out guidance, and backup/restore workflow note.
- Flip the use-hashed-tokens default in the config-options reference
  from false to true; rewrite intro and examples to reflect the new
  default.
- Add a Token hashing section to admin/tokens/ covering version
  defaults, startup behavior, opt-out, downgrade considerations, and
  recovery for lost tokens.
- Add a sitewide notification scoped to /influxdb/v2 and a cascade
  prepend on the /influxdb/v2 landing page that surface the change on
  every page in the v2 doc tree.
- Register --use-hashed-tokens in data/influxd_flags.yml so it
  appears in the influxd flag list.

Backup gzip compression:
- Document the new server-side Gzip-Compression-Level header and the
  influx backup --gzip-compression-level flag (influx-cli 2.8.0+) in
  the admin backup page and the shared CLI reference, including the
  --compression coupling.
- Note the regenerated v2 OpenAPI bundle in api-docs/, produced by
  api-docs/getswagger.sh after promoting influxdata/openapi#652 to
  docs-release/influxdb-oss. The /backup/metadata operation is still
  missing the parameter; tracked in influxdata/openapi#653.

Restore --operator-token:
- Document the new --operator-token flag (influx-cli 2.8.0+) in the
  admin restore page and the shared CLI reference, with explicit
  guidance for restoring backups whose operator token is hashed.

EDR replication:
- Note the new maxAgeSeconds bounds (60s–60d, 0 = use default) in the
  v2.9.0 release notes.

Version metadata:
- Bump data/products.yml: latest v2.8 -> v2.9, latest_patches.v2
  2.8.0 -> 2.9.0, latest_cli.v2 2.7.5 -> 2.8.0.

Refs influxdata/DAR#682

…rds endpoint

Surgical patch to api-docs/influxdb/v2/influxdb-oss-v2-openapi.yaml
adding the new Gzip-Compression-Level header parameter on
GET /api/v2/backup/shards/{shardID}, mirroring the upstream change in
influxdata/openapi#652.

The bundled YAML carries local Hugo-native customizations (title,
description, server URLs, tag descriptions with x-related doc links,
v2-scoped link paths) that get clobbered by api-docs/getswagger.sh.
Hand-applied here to preserve those customizations. The /backup/metadata
endpoint also receives this header in the server and CLI implementations
but is missing the parameter in the upstream spec; tracked in
influxdata/openapi#653.

Refs influxdata/DAR#682

* docs(influxdb/v2): document v2.9.0 release

Add v2.9.0 release notes and supporting docs for the InfluxDB OSS
2.9.0 release.

Token hashing default change:
- Add v2.9.0 release notes section with "Before you upgrade" callout,
  disable / opt-out guidance, and backup/restore workflow note.
- Flip the use-hashed-tokens default in the config-options reference
  from false to true; rewrite intro and examples to reflect the new
  default.
- Add a Token hashing section to admin/tokens/ covering version
  defaults, startup behavior, opt-out, downgrade considerations, and
  recovery for lost tokens.
- Add a sitewide notification scoped to /influxdb/v2 and a cascade
  prepend on the /influxdb/v2 landing page that surface the change on
  every page in the v2 doc tree.
- Register --use-hashed-tokens in data/influxd_flags.yml so it
  appears in the influxd flag list.

Backup gzip compression:
- Document the new server-side Gzip-Compression-Level header and the
  influx backup --gzip-compression-level flag (influx-cli 2.8.0+) in
  the admin backup page and the shared CLI reference, including the
  --compression coupling.
- Note the regenerated v2 OpenAPI bundle in api-docs/, produced by
  api-docs/getswagger.sh after promoting influxdata/openapi#652 to
  docs-release/influxdb-oss. The /backup/metadata operation is still
  missing the parameter; tracked in influxdata/openapi#653.

Restore --operator-token:
- Document the new --operator-token flag (influx-cli 2.8.0+) in the
  admin restore page and the shared CLI reference, with explicit
  guidance for restoring backups whose operator token is hashed.

EDR replication:
- Note the new maxAgeSeconds bounds (60s–60d, 0 = use default) in the
  v2.9.0 release notes.

Version metadata:
- Bump data/products.yml: latest v2.8 -> v2.9, latest_patches.v2
  2.8.0 -> 2.9.0, latest_cli.v2 2.7.5 -> 2.8.0.

Refs influxdata/DAR#682

* docs(influxdb/v2): add Gzip-Compression-Level parameter to backup shards endpoint

Surgical patch to api-docs/influxdb/v2/influxdb-oss-v2-openapi.yaml
adding the new Gzip-Compression-Level header parameter on
GET /api/v2/backup/shards/{shardID}, mirroring the upstream change in
influxdata/openapi#652.

The bundled YAML carries local Hugo-native customizations (title,
description, server URLs, tag descriptions with x-related doc links,
v2-scoped link paths) that get clobbered by api-docs/getswagger.sh.
Hand-applied here to preserve those customizations. The /backup/metadata
endpoint also receives this header in the server and CLI implementations
but is missing the parameter in the upstream spec; tracked in
influxdata/openapi#653.

Refs influxdata/DAR#682

* fix(influxdb/v2): correct broken #admin-token anchor in restore note

Update the operator-token link in admin/backup-restore/restore.md from
the non-existent `#admin-token` anchor to `#operator-token`, which
matches the actual heading on the tokens page.

The link prose still reads "admin token" as colloquial wording; only
the anchor target is corrected here.