fix(otel): use monotonic_counter prefix and support temporality env var

[codefromthecrypt]

Summary

This fixes a regression where most (not all) otel metrics were accidentally changed from monotonic_counter. to counter. and adds ENV support for metrics temporality preference.

The regression is subtle but made the metrics practically unusable for the things you'd actually want (rates, alerts, per-minute breakdowns).
For example, when monotonic a counter becomes a Prometheus counter, suppporting rate() and increase(), allowing you to build dashbaords like "tool calls per minute" or "sessions per hour".

Similar to our other ENV, this adds support for OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE
The default temporarilty is cumulative, which on export sends the total since the process start.
Backends who compute deltas internally, like Prometheus, expect this default.

delta only sends the delta since the last export, which is needed for backends like Elastic Stack and otel-tui.
When this isn't configurable, metrics are counted incorrectly, a total mistaken for a delta. This makes the metrics unusable.

Type of Change

• Bug fix

AI Assistance

• This PR was created or reviewed with AI assistance

Testing

• New temporality_preference_from_env parameterized tests

Related Issues

• Mnovich/otlp v2 #3772 — initial OTel PR (used correct monotonic_counter. prefix)
• additional metrics + Ui implementation #3871 — regressed prefix to counter. for all but one metric.
• feat(otel): respect standard OTel env vars for exporter selection #7144 — use ENV for otel config
• feat(otlp): support OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE open-telemetry/opentelemetry-rust#3351 — OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE in the SDK

[Copilot]

Pull request overview

This PR fixes a critical regression where most OTel metrics were accidentally changed from monotonic_counter. to counter. prefix, which broke Prometheus counter functionality (rate() and increase() functions). It also adds environment variable support for configuring metrics temporality preference via OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE.

Changes:

• Corrected metric prefix from counter. back to monotonic_counter. across all telemetry instrumentation points
• Added temporality preference configuration via environment variable with support for delta, cumulative, and lowmemory modes
• Comprehensive parameterized tests for temporality preference parsing

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/goose/src/otel/otlp.rs	Added temporality_preference() function to read ENV var, applied temporality to OTLP metrics exporter, added comprehensive test coverage
crates/goose/src/security/mod.rs	Fixed metric prefixes from counter. to monotonic_counter. for security scanner metrics (5 locations)
crates/goose/src/agents/tool_execution.rs	Fixed metric prefix for prompt_injection_user_decisions counter
crates/goose-server/src/routes/schedule.rs	Fixed metric prefix for recipe_runs counter
crates/goose-server/src/routes/reply.rs	Fixed metric prefixes for session and tool metrics (7 locations)
crates/goose-cli/src/session/mod.rs	Fixed metric prefixes for tool_calls and tool_completions counters
crates/goose-cli/src/cli.rs	Fixed metric prefixes for session and CLI command metrics (7 locations)