docs: document Tempo HTTP API and Grafana Traces Drilldown

[vshulakov-sh]

Describe Your Changes

Closes #191.

Since v0.9.0 VictoriaTraces extended its Tempo API / TraceQL support, enabling the Grafana Tempo datasource and the Grafana Traces Drilldown feature, but this was not yet documented. This PR documents it:

• Adds a "Tempo HTTP API" section to the querying docs listing all supported /select/tempo/* endpoints, the version each was introduced in, and how they work — trace search (TraceQL), tag/value auto-completion, trace-by-id (v1 & v2), and TraceQL metrics — with curl examples and the TraceQL → LogsQL attribute mapping.
• Expands the Grafana Tempo datasource doc with cluster (vtselect) URL guidance and a "Grafana Traces Drilldown" setup section that links to the endpoints it relies on.

Docs only — no code or behavior changes.

Checklist

The following checks are mandatory:

• My change adheres to VictoriaMetrics contributing guidelines.
• My change adheres to VictoriaMetrics development goals.

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="docs/victoriatraces/querying/README.md">

<violation number="1" location="docs/victoriatraces/querying/README.md:260">
P2: The example claims to query traces 'over the last hour' but omits `start` and `end` parameters. Per the documented defaults, omitting these parameters searches only the last 10 minutes, creating a mismatch between the example description and actual behavior.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>

[cubic-dev-ai]

P2: The example claims to query traces 'over the last hour' but omits start and end parameters. Per the documented defaults, omitting these parameters searches only the last 10 minutes, creating a mismatch between the example description and actual behavior.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At docs/victoriatraces/querying/README.md, line 260:

<comment>The example claims to query traces 'over the last hour' but omits `start` and `end` parameters. Per the documented defaults, omitting these parameters searches only the last 10 minutes, creating a mismatch between the example description and actual behavior.</comment>

<file context>
@@ -221,6 +221,101 @@ Some valid filter examples:
+- `start`, `end`: the time range boundaries as Unix timestamps. When omitted, the last 10 minutes are used.
+- `limit`: the maximum number of traces to return, clamped to the `[0, 1000]` range. Default `100`.
+
+For example, to find traces of the `frontend` service with status `error` over the last hour:
+
+```sh
</file context>

Suggested change

	For example, to find traces of the `frontend` service with status `error` over the last hour:
	+For example, to find traces of the `frontend` service with status `error` over the last 10 minutes: