feat(pipeline): add Meltano + dbt + Airflow ELT pipeline scaffold

Replaces the hand-rolled integrator with a production-grade ELT pipeline
using Meltano (Singer taps), dbt Core (medallion architecture), and
Apache Airflow (orchestration). Adds Typesense for search and PostGIS
for geospatial queries.

- 6 custom Singer taps (GIAS, EES, Ofsted, Parent View, FBIT, IDACI)
- dbt project: 12 staging, 5 intermediate, 12 mart models
- 3 Airflow DAGs (daily/monthly/annual schedules)
- Typesense sync + batch geocoding scripts
- docker-compose: add Airflow, Typesense; upgrade to PostGIS
- Portainer stack definition matching live deployment topology

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pipeline/transform/models/intermediate/int_ks2_with_lineage.sql

@@ -0,0 +1,62 @@
+-- Intermediate model: KS2 data chained across academy conversions
+-- Maps predecessor URN data to the current active URN
+
+with current_ks2 as (
+    select
+        urn as current_urn,
+        urn as source_urn,
+        year,
+        total_pupils,
+        rwm_expected_pct,
+        reading_expected_pct,
+        writing_expected_pct,
+        maths_expected_pct,
+        rwm_high_pct,
+        reading_high_pct,
+        writing_high_pct,
+        maths_high_pct,
+        reading_progress,
+        writing_progress,
+        maths_progress,
+        reading_avg_score,
+        maths_avg_score
+    from {{ ref('stg_ees_ks2') }}
+),
+
+predecessor_ks2 as (
+    select
+        lin.current_urn,
+        ks2.urn as source_urn,
+        ks2.year,
+        ks2.total_pupils,
+        ks2.rwm_expected_pct,
+        ks2.reading_expected_pct,
+        ks2.writing_expected_pct,
+        ks2.maths_expected_pct,
+        ks2.rwm_high_pct,
+        ks2.reading_high_pct,
+        ks2.writing_high_pct,
+        ks2.maths_high_pct,
+        ks2.reading_progress,
+        ks2.writing_progress,
+        ks2.maths_progress,
+        ks2.reading_avg_score,
+        ks2.maths_avg_score
+    from {{ ref('stg_ees_ks2') }} ks2
+    inner join {{ ref('int_school_lineage') }} lin
+        on ks2.urn = lin.predecessor_urn
+    -- Only include predecessor data for years before the current URN has data
+    where not exists (
+        select 1 from {{ ref('stg_ees_ks2') }} curr
+        where curr.urn = lin.current_urn
+          and curr.year = ks2.year
+    )
+),
+
+combined as (
+    select * from current_ks2
+    union all
+    select * from predecessor_ks2
+)
+
+select * from combined

pipeline/transform/models/intermediate/int_ks4_with_lineage.sql

@@ -0,0 +1,50 @@
+-- Intermediate model: KS4 data chained across academy conversions
+
+with current_ks4 as (
+    select
+        urn as current_urn,
+        urn as source_urn,
+        year,
+        total_pupils,
+        progress_8_score,
+        attainment_8_score,
+        ebacc_entry_pct,
+        ebacc_achievement_pct,
+        english_strong_pass_pct,
+        maths_strong_pass_pct,
+        english_maths_strong_pass_pct,
+        staying_in_education_pct
+    from {{ ref('stg_ees_ks4') }}
+),
+
+predecessor_ks4 as (
+    select
+        lin.current_urn,
+        ks4.urn as source_urn,
+        ks4.year,
+        ks4.total_pupils,
+        ks4.progress_8_score,
+        ks4.attainment_8_score,
+        ks4.ebacc_entry_pct,
+        ks4.ebacc_achievement_pct,
+        ks4.english_strong_pass_pct,
+        ks4.maths_strong_pass_pct,
+        ks4.english_maths_strong_pass_pct,
+        ks4.staying_in_education_pct
+    from {{ ref('stg_ees_ks4') }} ks4
+    inner join {{ ref('int_school_lineage') }} lin
+        on ks4.urn = lin.predecessor_urn
+    where not exists (
+        select 1 from {{ ref('stg_ees_ks4') }} curr
+        where curr.urn = lin.current_urn
+          and curr.year = ks4.year
+    )
+),
+
+combined as (
+    select * from current_ks4
+    union all
+    select * from predecessor_ks4
+)
+
+select * from combined

pipeline/transform/models/intermediate/int_ofsted_latest.sql

@@ -0,0 +1,37 @@
+-- Intermediate model: Latest Ofsted inspection per URN
+-- Picks the most recent inspection for each school
+
+with ranked as (
+    select
+        *,
+        row_number() over (
+            partition by urn
+            order by inspection_date desc
+        ) as rn
+    from {{ ref('stg_ofsted_inspections') }}
+)
+
+select
+    urn,
+    inspection_date,
+    inspection_type,
+    framework,
+    overall_effectiveness,
+    quality_of_education,
+    behaviour_attitudes,
+    personal_development,
+    leadership_management,
+    early_years_provision,
+    sixth_form_provision,
+    rc_safeguarding_met,
+    rc_inclusion,
+    rc_curriculum_teaching,
+    rc_achievement,
+    rc_attendance_behaviour,
+    rc_personal_development,
+    rc_leadership_governance,
+    rc_early_years,
+    rc_sixth_form,
+    report_url
+from ranked
+where rn = 1

pipeline/transform/models/intermediate/int_pupil_chars_merged.sql

@@ -0,0 +1,18 @@
+-- Intermediate model: Merged pupil characteristics from census data
+
+select
+    urn,
+    year,
+    fsm_pct,
+    sen_support_pct,
+    sen_ehcp_pct,
+    eal_pct,
+    disadvantaged_pct,
+    ethnicity_white_pct,
+    ethnicity_asian_pct,
+    ethnicity_black_pct,
+    ethnicity_mixed_pct,
+    ethnicity_other_pct,
+    class_size_avg,
+    stability_pct
+from {{ ref('stg_ees_census') }}

pipeline/transform/models/intermediate/int_school_lineage.sql

@@ -0,0 +1,48 @@
+-- Intermediate model: Recursive predecessor mapping
+-- Resolves academy conversion chains so historical data can be attributed
+-- to the current (active) URN.
+
+with recursive lineage as (
+    -- Base: schools that are predecessors (linked via academy conversion, amalgamation, etc.)
+    select
+        urn,
+        linked_urn as predecessor_urn,
+        link_type,
+        link_date,
+        1 as depth
+    from {{ ref('stg_gias_links') }}
+    where link_type in (
+        'Predecessor',
+        'Predecessor - Loss of academy converter',
+        'Predecessor - amalgamated',
+        'Predecessor - Fresh Start'
+    )
+
+    union all
+
+    -- Recursive step: follow the chain
+    select
+        l.urn,
+        links.linked_urn as predecessor_urn,
+        links.link_type,
+        links.link_date,
+        l.depth + 1
+    from lineage l
+    inner join {{ ref('stg_gias_links') }} links
+        on l.predecessor_urn = links.urn
+    where links.link_type in (
+        'Predecessor',
+        'Predecessor - Loss of academy converter',
+        'Predecessor - amalgamated',
+        'Predecessor - Fresh Start'
+    )
+    and l.depth < 5  -- safety limit
+)
+
+select
+    urn as current_urn,
+    predecessor_urn,
+    link_type,
+    link_date,
+    depth
+from lineage